Dental impression tray

ABSTRACT

The invention relates to a dental impression tray comprising a base and at least two walls defining said base. At least one of these walls is at least partially formed by hollow bodies made of flexible material. Said hollow bodies can be filled in order to form, when taut, the desired shape for using the mould tray. In order to provide sufficient longitudinal stability for the impression tray, at least one of the walls is fitted with a rigid longitudinal rib. Said wall can also be rigid in its entirety. The hollow bodies which are to be filled can be fitted with openings. The moulding material filling the hollow bodies can flow from said openings into the moulding region of the dental impression tray. The base is flexible.

CROSS REFERENCE TO RELATED APPLICATION

This application is a 371 of PCT/EP02/06267 filed Jun. 7, 2002.

BACKGROUND OF THE INVENTION

To obtain impressions of teeth in order to produce a denture, use ismade of impression compounds which harden from a pasty state. In orderto hold the impression compound in the area of the teeth from which theimpression is being taken, impression trays are used. These consist of abase and of at least two side walls which together enclose theimpression area into which the impression compound is introduced so asto be brought, held by the tray, to the impression site. The walls, oneof which comes to lie on the lingual/palatal aspect and the other on thebuccal aspect of the teeth from which the impression is to be taken, areintended to ensure that the compound cannot flow out but is instead heldat the sides of the teeth from which the impression is to be taken. Itis known (DE-A-196 08 546) to provide, in the tray, a delivery tube forthe compound, which delivery tube is provided with a row of outletopenings distributed along the length of the tray.

As a result of the closing of the dentition during impression-taking,the teeth from which the impression is to be taken force themselves intothe impression compound. This is not successfully accomplished if thepatient bites on one of the two walls and, accordingly, the teeth fromwhich the impression is to be taken do not penetrate into the spacebetween the walls. This risk arises in known impression trays which aremade of a rigid material such as metal or plastic. If, according to aknown proposal (DE-C-31 04 721), the compound is enclosed entirelywithin a flexible tube, the tube material located between the compoundand the teeth forms an obstacle to a clean impression. Furthermore, theunpublished prior art includes the proposal that fixed walls be avoidedby means of the walls being formed by inflatable tube elements.

Compressed air, water or else impression compound can be used to fillthe tube elements. However, it has been found that, on account of thelack of shape stability of such impression trays, the impressioncompound is not securely held and, for example, flows out over thewalls. The impression material does not then attain the desired height,and the impression-taking is not completely successful.

SUMMARY OF THE INVENTION

Accordingly, provision is made for at least one of the walls to have arigid longitudinal rib. This longitudinal rib can form part of the wall,which is otherwise formed for example by a tube element which is to befilled, or it can be an insert of such a tube. It can also form thewhole of the wall in question. The wall which is of rigid design or isequipped to be rigid is preferably the wall located on thelingual/palatal aspect. However, instead of or in addition to this, thewall on the buccal aspect can also be equipped to be rigid. The base ofthe tray is formed by flexible material. Apart from avoiding thedisadvantages of the prior art, this ensures that the tray can be packedwithin a very small space and can easily be made ready for use.

The wall which is erected by filling comprises at least one tube elementwhose interior communicates with a filling opening. This filling openingcan for example be attached to a dispensing appliance for impressioncompound. To use the tray, the tube element is filled with theimpression compound and thereby assumes the taut and sufficientlyshape-stable state.

As soon as the impression tray has reached this state, its impressionarea can be provided in a customary manner with the required amount ofimpression compound, for example by being held under the nozzle of asuitable dispensing appliance. According to the invention, it is moreadvantageous if the tube element to be filled with the impressioncompound has at least one outflow opening directed toward the impressionarea of the tray. After the tube element has been filled, the impressioncompound passes through this opening and into the impression area of thetray and finally fills the latter. A row of such outflow openings isexpediently distributed along the length of the impression area of thetray so as to achieve uniform filling. If the tube element is arrangedonly on one side of the tray, it is provided with these outflow openingson its side directed toward the impression area. In order to achieve acomplete and sufficiently rigidifying filling of the tube element, itmay be more expedient, however, to guide this around the narrow end ofthe tray directed away from the filling opening and even, ifappropriate, route it back on the other side. Substantially the wholelength of the wall in question should lie between the filling openingand the outflow opening so that it becomes taut as a result of thepressure drop in the outflow opening or outflow openings before thematerial can flow into the impression area. If the tube element in thearea of the rigid wall is routed back in the direction toward that endof the tray provided with the filling opening, the outflow openings areexpediently arranged on the side of the rigid wall.

When it flows out of the tube element into the impression area of thetray, the compound should meet a certain resistance, which ensures that,at least during the filling procedure, a certain overpressure prevailsin the tube element and guarantees the tautness and rigidity of the tubeelement. Slit-shaped outlet openings have proven expedient, preferablyextending in the transverse direction (relative to the direction of thetube element). According to another feature of the invention, theoutflow openings can form mouths or channels or nozzles projecting intothe impression area of the tray. On the one hand, this guarantees aparticularly uniform filling of the impression area, on the other handit creates the desired pressure difference. Finally, according to theinvention it is possible to provide the outflow opening(s) with aburstable seal, for example a burstable membrane. The burstable sealopens only when a predetermined overpressure is reached in the tubeelement, so that its tautness is in this way ensured.

It is recommended to ensure complete filling of the tube element withimpression compound, and this presupposes removal of air. If outflowopenings toward the impression area of the tray are provided, the air isremoved through these outflow openings. Tube elements with a blind endshould be provided with a special vent hole which is expedientlydesigned in such a way that it prevents impression compound beingpressed out. This can be achieved, for example, by the vent hole beingvery small or being provided with a suitable valve.

The filling opening is expediently designed for fitted attachment to adispensing appliance for impression compound. If the dispensing nozzleof this appliance ends in a cone shape, a tube end forming the fillingopening can for example be pushed onto the conical nozzle end. Aform-fit coupling can also be provided, for example with a bayonet catchand sealing surfaces. During handling of the tray, escape of impressioncompound from the filling opening must be prevented. This can beachieved using a self-closing valve, for example, analogously to thedesign of the filling valve, so-called valve sacks. A special closureclip can also be provided which is placed from outside onto the tubepart forming the filling openings in order to press it together. Or astopper can be provided. If it is connected to the tube part in asufficiently shape-stable manner, it can according to the invention beprovided with a grip via which the entire tray can be handled.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail below with reference to thedrawing which depicts advantageous illustrative embodiments. In thedrawing:

FIG. 1 shows the perspective view of a first embodiment,

FIG. 2 shows a cross section through the first embodiment,

FIG. 3 shows the perspective representation of a second embodiment,

FIG. 4 shows a cross section through the second embodiment, and

FIG. 5 shows a third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The impression tray according to FIGS. 1 and 2 has a base 1 which can beformed for example by a flexible foil or a piece of fabric. On thelingual/palatal side, the plate 1 is delimited by a wall 2 formed by arigid structural part. It is substantially plate-shaped. It forms alongitudinal rib which renders the tray rigid. Rigid in this context isto be understood as meaning a strength which permits a sufficient shapestability of this wall under the forces which occur. Suitable materialsare polyethylene, polyvinyl chloride, cardboard or the like.

The base 1 is delimited on the buccal side by a tube element 3. The tubeelement 3 extends along the entire length of the base 1 and alsoencloses its rear edge 4. It ends in the connection to the wall part 2.The tube portion 4 ensures the lateral tensioning of the tray betweenthe wall 2 and the tube element 3 when the base 1 is too flexible to beable to satisfy this task.

At the front end, the tube element 3 communicates with a filling tube 5whose end 6 forms the filling opening. The tube 5 can be pushed with theopening 6 over the conical end of a filler nozzle. Also shown is closingelement 9 which can be a self-closing valve, a closure clip, or astopper with a grip via which the entire tray can be handled.

Provided at the end of the tube element 3 or tube portion 4 there is anopening 7 which points toward the impression area of the tray formed bythe base 1. It is either so small that no appreciable amounts ofimpression compound can escape from it, and it then serves only forremoval of air. Or it is so large that the impression compound can flowout in the amount required for the impression and can fill theimpression area.

Instead of this, the tube element 3 could also be provided with aplurality of outflow openings along its length which point toward theupper face of the base 1 in order to deliver the required amount ofimpression compound uniformly to the impression area.

The illustrative embodiment according to FIGS. 3 and 4 is identical tothe above-described embodiment in respect of the base 1, the wall 2, thetube element 3 and the filling tube 5. Adjoining the rear end of thetube element 3 there is once again a tube portion 4 which stiffens therear narrow end of the device. This is adjoined by a tube element 8which runs along the inner side of the wall 2 as far as the front endand has a plurality of outflow openings 7 which protrude into theimpression area in the form of projecting mouths or nozzles and permituniform delivery of impression compound to this area.

The filling tube 5, the tube element 3, the tube portion 4 and the tubeelement 8 can be made in one piece, in which case the differentdiameters are generated by different expansion.

In the third embodiment according to FIG. 5, the projecting mouths 9according to the above-described embodiment are lengthened in the formof channels 10 which extend in uniform distribution transversely acrossthe base 1. They include slit openings 11, of which the drawingindicates one per channel 10. It will be appreciated that several suchopenings can be distributed across the surface of the base 1. With theslit-shaped configuration of the openings 11, these are expedientlyarranged transversely with respect to the longitudinal extent of thechannels containing them.

1. A dental impression tray having a lingual/palatal side and a generally opposite buccal side, and a base wherein either said lingual/palatal side or said buccal side consists of a first wall and the other said side consists of a second wall, the first wall being stiff in its entirety and forming a longitudinal rib, characterized in that the first wall is substantially plate-shaped, and the second wall is formed of flexible material which is filled with impression compound in order to assume, in a taut state, a stable shape to enable filling of the tray, and the base is being made of flexible material.
 2. The tray as claimed in claim 1, characterized in that the first wall is located on the lingual/palatal side.
 3. The tray as claimed in claim 2, characterized in that the tillable wall comprises at least one tube element whose interior communicates with a filling opening.
 4. The tray as claimed in claim 1, characterized in that it has a tube part with a blind end and with a vent hole.
 5. The tray as claimed in claim 4, characterized in that the vent hole is designed as a valve obstructing the outflow of impression compound.
 6. The tray as claimed in claim 1, characterized in that the second wall comprises at least one tube element whose interior communicates with a filling opening.
 7. The tray as claimed in claim 6, characterized in that the filling opening is designed for fitted attachment to a dispensing appliance for impression compound.
 8. The tray as claimed in claim 7, characterized in that the filling opening or the filling tube is provided with a closure device.
 9. The tray as claimed in claim 8, characterized in that the closure device is a self-closing valve.
 10. The tray as claimed in claim 8, characterized in that the closure device is a closure clip.
 11. The tray as claimed in claim 8, characterized in that the closure device is equipped with a grip for the tray.
 12. The tray as claimed in claim 6, characterized in that at least one tube element has an interior which communicates with at least one outflow opening directed toward an impression area of the tray.
 13. The tray as claimed in claim 12, characterized in that an outflow opening is provided with a burstable seal.
 14. The tray as claimed in claim 12, wherein the impression area has a length and characterized in that a row of outflow openings is distributed along the length of the impression area of the tray.
 15. The tray as claimed in claim 14, characterized in that a tube element in the area of the rigid wall is routed back in the direction toward that end of the tray provided with the filling opening.
 16. The tray as claimed in claim 14, characterized in that the outflow openings are designed as slits.
 17. The tray as claimed in claim 14, characterized in that the outflow openings form mouths projecting into the impression area of the tray. 